REFLEXES, INSTINCT, AND REASON 433 



instinctively: This may be because all ponies which have not 

 this reflex dislike have been destroyed. The imported horse 

 has no such instinct and is poisoned. Very few animals will 

 eat any poisonous object with which their instincts are familiar, 

 unless it be concealed from smell and taste. 



In some cases, very elaborate instincts arise in connection 

 with feeding habits. In the case of the California woodpeckers 

 (Melanerpes formicivorus bairdii) a large number together select 

 a live-oak tree for their operations. They first bore its bark 

 full of holes, each large enough to hold an acorn. Then into 

 each hole an acorn is thrust (Figs. 267 r.nd 268). Only one tree 

 in several square miles may be selected, and when their work is 

 finished all those interested go about their business elsewhere. 

 At irregular intervals a dozen or so come back with much 

 clamorous discussion to look at the tree. When the right time 

 comes, they all return, open the acorns one by one, devouring 

 apparently the substance of the nut, and probably also the 

 grubs of beetles which have developed within. When the nuts 

 are ripe, again they return to the same tree and the same 

 process is repeated. In the tree figured this has been noticed 

 each year since 1891. 



The instinct of self-defense is even more varied in its mani- 

 festations. It may show itself either in the impulse to make 

 war on an intruder or in an impulse to flee from its enemies. 

 Among the flesh-eating mammals and birds fierceness of de- 

 meanor serves both for the securing of food and for protection 

 against enemies. The stealthy movements of the lion, the 

 skulking habits of the wolf, the sly selfishness of the fox, the 

 blundering good-natured power of the bear, the greediness of 

 the hyena, are all proverbial, and similar traits in the eagle, 

 owl, hawk, and vulture are scarcely less matters of common 

 observation. 



Herbivorous animals, as a rule, make little direct resistance 

 to their enemies, depending rather on swiftness of foot, or in 

 some cases on simple insignificance. To the latter cause the 

 abundance of mice and mouselike rodents may be attributed, 

 for all are the prey of the carnivorous beasts and birds, and 

 of snakes. 



Even young animals of any species show great fear of their 

 hereditary enemies. The nestlings in a nest of the American 

 bittern when one week old showed no fear of man, but when 



